This invention relates to certain novel compounds, to a process for preparing such compounds, to pharmaceutical compositions containing such compounds and to the use of such compounds and compositions in medicine.
Diseases associated with loss of bone mass are known to be caused by over activity of osteoclast cells. It is also known that certain compounds, usually related to bafilomycin, are useful for treating such diseases. For example, International Application Publication Number WO 91/06296 (Aktiebolaget Astra) discloses certain bafilomycin macrolides for the treatment of bone affecting diseases.
However, bafilomycin derivatives are not selective for osteoclasts in humans. The use of these compounds is therefore associated with unacceptable toxicity due to generalised blockade of other essential v-ATPases. Indeed, to date there is no known treatment which is selective for the human osteoclasts.
The search for a successful treatment for diseases associated with loss of bone mass in humans is further complicated in that the nature of the therapeutic target for the selective inhibition of the osteoclasts is controversial. Thus Baron et al (International Application Publication Number WO 93/01280) indicate that a specific vacuolar ATPase (v-ATPase) has been identified in osteoclasts as a potential therapeutic target. However, the Baron work was carried out in chickens and Hall et al (Bone and Mineral 27, 159-166, (1994)), in a study relating to mammals, conclude that in contrast to avian osteoclast v-ATPase, mammalian osteoclast v-ATPase is pharmacologically similar to the v-ATPase in other cells and, therefore, it is unlikely to be a good therapeutic target.
It has now surprisingly been found that particular indole compounds are selective for mammalian osteoclasts, acting to selectively inhibit their bone resorbing activity. These compounds are therefore considered to be particularly useful for the treatment and/or prophylaxis of diseases associated with loss of bone mass, such as osteoporosis and related osteopenic diseases, Paget""s disease, hyperparathyroidism and related diseases. These compounds are also considered to possess antitumour activity, antiviral activity (for example against Semliki Forest, Vesicular Stomatitis, Newcastle Disease, Influenza A and B, HIV viruses), antiulcer activity (for example the compounds may be useful for the treatment of chronic gastritis and peptic ulcer induced by Helicobacter pylori), immunosupressant activity, antilipidemic activity, antiatheroscierotic activity and to be useful for the treatment of AIDS and Alzheimer""s disease. Furthermore, these compounds are also considered useful in inhibiting angiogenesis i.e. the formation of new blood vessels which is observed in various types of pathological conditions (angiogenic diseases) such as rheumatoid arthritis, diabetic retinopathy, psoriasis and solid tumours.
Accordingly, the invention provides a compound of formula (I) 
or a salt thereof, or a solvate thereof,
wherein;
R1 and R2 each independently represents C1-6alkoxy or halo;
R3 and R4 each independently represents hydrogen, C1-6alkoxy, arylC1-6alkoxy, hydroxy, carboxyC1-6alkoxy, hydroxyC1-6alkoxy, dihydroxyC1-6alkoxy, mono-and di-(C1-6alkyl)aminoC1-6alkoxy or aminoC1-6alkoxy, and;
R5 represents xe2x80x94NRsRt wherein Rs and Rt each independently represent hydrogen, unsubstituted or substituted C1-6alkyl, or unsubstituted or substituted heterocyclyl.
Suitably, R1 and R2 each independently represents methoxy or chloro.
Suitable positions for substitution for R1 or R2 are the 4, 5, 6 or 7 position.
Favourably R1 or R2 are at the 5 or 6 position.
Preferably, R1 is 5-chloro and R2 is 6-chloro.
Suitably, R3 is hydroxy, methoxy, ethoxy, propoxy, benzyloxy, carboxyethoxy, hydroxyethoxy, dihydroxypropoxy, dimethylaminoethoxy or aminopropoxy.
Suitably, R3 is located ortho or meta to the xe2x80x94COR5 moiety.
Suitably, R4 is hydrogen or methoxy.
Suitably, R4 is located meta to the xe2x80x94COR5 moiety.
Suitably, Rs or Rt represent unsubstituted or substituted C1-6alkyl, or unsubstituted or substituted heterocyclyl.
When Rs or Rt represent unsubstituted or substituted C1-6alkyl, suitable C1-6alkyl groups are ethyl, propyl and butyl.
When Rs or Rt represent substituted alkyl, favoured groups are 3-[4(3-methoxyphenyl)piperzin-1-yl]propyl and 3-[4-(2-pyrimidinyl)piperazin-1-yl]propyl.
Suitably, Rs or Rt represent an unsubstituted or substituted piperidinyl group.
Favourably, Rs or Rt represent an unsubstituted or substituted 4-piperidinyl group.
When Rs or Rt represent a substituted piperidinyl group, suitable substituents include C1-6alkyl, fused C3-8cycloalkyl, arylC1-6alkyl, hydroxyC1-6alkyl, polyhydroxyC1-6alkyl, C1-6alkoxycarbonylC1-6alkyl, carboxyC1-6alkyl, and aminoC1-6alkyl.
Favoured substituents for piperidinyl groups are C1-6alcyl groups, especially methyl groups.
When Rs or Rt represent a substituted piperidinyl group, it is preferred that the substituents are attached to one or both of the carbon atoms alpha to the nitrogen atom.
Examples of substituted piperidinyl groups are 1,2,2,6,6-pentamethylpiperidin-4-yl and 2,2,6,6-tetramethylpiperidin-4-yl groups.
Favourably, Rt is hydrogen.
There is a subgroup of compounds falling wholly within formula (I), being of formula (Ixe2x80x2) 
wherein;
R1, R2, R3, R4, and R5 are as defined in formula (I), with the proviso that formula (Ixe2x80x2) does not include;
4-(5,6-dichloro-1H-indol-2-yl)-N-(1,2,2,6,6-pentamethylpiperidin-4-yl)benzamide;
4-(5,6-dichloro-1H-indol-2-yl)-3-methoxy-N-(1,2,2,6,6-pentamethylpiperidin-4-yl)benzamide;
4-(5,6-dichloro-1H-indol-2-yl)-2-methoxy-N-(1,2,2,6,6-pentamethylpiperidin-4-yl)benzamide;
4-(5,6-dichloro-1H-indol-2-yl)-3-methoxy-N-(3-diethylaminopropyl)benzamide;
4-(5,6-dichloro-1H-indol-2-yl)-2-methoxy-N-(3-diethylaminopropyl)benzamide;
4-(5,6-dichloro-1H-indol-2-yl)-3-methoxy-N-[3-[4-(3-chlorophenyl)piperazinyl]propyl]benzamide;
4-(5,6-dichloro-1H-indol-2-yl)-2-methoxy-N-[3-[4-(3-chlorophenyl)piperazinyl]propyl]benzamide;
4-(5,6-dichloro-1H-indol-2-yl)-3-methoxy-N-(2,2,6,6-tetramethylpiperidin-4-yl)-N-methylbenzamide, or;
4-(5,6-dichloro-1H-indol-2-yl)-2-methoxy-N-(2,2,6,6-tetramethylpiperidin-4-yl)-N-methylbenzamide.
It is considered that compounds of formula (Ixe2x80x2) are novel. Accordingly, the present invention provides a compound of formula (Ixe2x80x2) or a salt thereof or a solvate thereof.
There is a subgroup of compounds falling wholly within formula (I) of formula (IA) 
wherein;
R1, R2, R3, R4, and R5 are as defined in formula (I), Rs is 3-[4-(3-methoxyphenyl)piperazin-1-yl]propyl or 3-[4-(2-pyrimidinyl)piperazin-1-yl]propyl, and Rt is hydrogen. It is considered that compounds of formula (IA) are novel.
Accordingly, the present invention provides a compound of formula (IA) or a salt thereof or a solvate thereof.
There is a subgroup of compounds falling wholly within formula (I) of formula (IB) 
wherein;
R1, R2, R3, R4, and R5 are as defined in formula (I), Rs is 3-pyridyl or 3-(6-methoxy)pyridyl, and Rt is hydrogen. It is considered that compounds of formula (IB) are novel.
Accordingly, the present invention provides a compound of formula (IB) or a salt thereof or a solvate thereof.
There is a subgroup of compounds falling wholly within formula (I) of formula (IC) 
wherein;
R2, R4, and R5 are as defined in formula (I), Rs is 2,2,6,6-tetramethylpiperidin-4-yl, Rt is hydrogen, R3 is 3-ethoxy, and R1 is 5-chloro or 5-methoxy. It is considered that compounds of formula (IC) are novel.
Accordingly, the present invention provides a compound of formula (IC) or a salt thereof or a solvate thereof.
There is a subgroup of compounds falling wholly within formula (I) of formula (ID) 
wherein;
R1, R2, R4, and R5 are as defined in formula (I), Rs is 2,2,6,6-tetramethylpiperidin-4-yl, Rt is hydrogen, R3 is 2-methoxy, 3-methoxy, 3-ethoxy, 3-propoxy, 3-benzyloxy, 3-(2-carboxyethoxy), 3-(2-hydroxyethoxy), 3-(2,3-dihydroxypropoxy), 3-(2-dimethylaminoethoxy) or 3-(3-aminopropoxy) and 3-hydroxy and R4 is 5-methoxy or hydrogen. It is considered that compounds of formula (ID) are novel.
Accordingly, the present invention provides a compound of formula (ID) or a salt thereof or a solvate thereof.
There is a subgroup of compound falling wholly within formula (I) of formula (IE) 
wherein;
R1, R2, R4, and R5 are as defined in formula (I), Rs is 1,2,2,6,6-pentamethylpiperidin-4-yl, Rt is hydrogen, and R3 is 2-methoxy or 3-ethoxy, and R4 is 5-methoxy or hydrogen. It is considered that compounds of formula (IE) are novel.
Accordingly, the present invention provides a compound of formula (IE) or a salt thereof or a solvate thereof.
There is a subgroup of compounds falling wholly within formula (I) of formula (IF) 
wherein;
R1, R2, R3, R4, and R5 are as defined in formula (I), Rs is 1-benzylpiperidin-4-yl, 1-(4-ethoxycarbonyl)butylpiperydin-4-yl, 1-(4-hydroxycarbonyl)butylpiperydin-4-yl and Rt is hydrogen. It is considered that compounds of formula (IF) are novel.
Accordingly, the present invention provides a compound of formula (IF) or a salt thereof or a solvate thereof.
As used herein, the term xe2x80x9calkylxe2x80x9d includes straight or branched chain alkyl groups having from 1 to 12, suitably 1 to 6, preferably 1 to 4, carbon atoms, such as methyl, ethyl, n- and iso-propyl and n- iso-, tert-butyl and pentyl groups, and also includes such alkyl groups when forming part of other groups such as alkoxy or alkanoyl groups.
Suitable substituents for any alkyl groups include heterocyclyl groups, for example piperazinyl.
As used herein, the term xe2x80x9carylxe2x80x9d includes phenyl and naphthyl, especially phenyl.
Suitable optional substituents for any aryl group include up to 5 substituents, suitably up to 3 substituents, selected from alkyl, alkoxy, thioalkyl, hydroxy, halo, aryl, heterocyclyl, trifluoromethyl, alkylcarbonyl, cyano, nitro, or a group xe2x80x94NRuRv wherein Ru and Rv each independently represent hydrogen, alkyl or alkylcarbonyl.
Suitable arylalkyl groups include phenylethyl and benzyl groups, especially benzyl. Preferably, substituted aralkyl groups are substituted in the aryl moiety.
As used herein, the terms xe2x80x9cheterocyclicxe2x80x9d and xe2x80x9cheterocyclylxe2x80x9d include saturated or unsaturated single or fused ring heterocyclic groups, each ring having 4 to 11 ring atoms, especially 5 to 8, preferably 5, 6 or 7 which ring atoms include 1, 2 or 3 heteroatoms selected from O, S, or N. Examples of such groups include piperidyl, pyridyl, piperazinyl, and pyrimidinyl.
Suitable optional substituents for any heterocyclyl group includes those mentioned herein with respect to the aryl group.
As used herein, the term xe2x80x9chalogenxe2x80x9d or xe2x80x9chaloxe2x80x9d includes fluoro, chloro, bromo and iodo, suitably fluoro and chloro, favourably chloro.
When used herein xe2x80x9cacylxe2x80x9d includes alkyl carbonyl.
Certain of the compounds of formula (I) may contain chiral atoms and/or multiple bonds and may therefore exist as stereoisomers. The invention extends to all stereoisomeric forms of the compounds of formula (I) including geometric isomers, diastereoisomers, enantiomers and mixtures thereof, including racemic modifications. Stereoisomers may be separated or resolved by conventional methods or any given isomer may be obtained by conventional stereospecific or asymmetric syntheses.
Suitable salts are pharmaceutically acceptable salts.
Suitable pharmaceutically acceptable salts include acid addition salts and salts of carboxy groups.
Suitable pharmaceutically acceptable acid addition salts include salts with inorganic acids such, for example, as hydrochloric acid, hydrobromic acid, orthophosphoric acid or sulphuric acid, or with organic acids such, for example as methanesulphonic acid, toluenesulphonic acid, acetic acid, propionic acid, lactic acid, citric acid, fumaric acid, malic acid, succinic acid, salicylic acid, maleic acid, glycerophosphoric acid or acetylsalicylic acid.
Suitable pharmaceutically acceptable salts of carboxy groups include metal salts, such as for example aluminium, alkali metal salts such as sodium or potassium and lithium, alkaline earth metal salts such as calcium or magnesium and ammonium or substituted ammonium salts, for example those with C1-6alkylamines such as triethylamine, hydroxyC1-6alkylamines such as 2-hydroxyethylamine, bis(2-hydroxyethyl)amine or tri(2-hydroxyethyl)amine, cycloalkylamines such as dicyclohexylamine, or with procaine, 1,4-dibenzylpiperidine, N-benzyl-b-phenethylamine, dehydroabietylamine, N,Nxe2x80x2-bisdehydroabietylamine, glucamine, N-methylglucamine, or bases of the pyridine type such as pyridine, collidine, or quinoline.
Suitable solvates of the compounds of the formula (I) are pharmaceutically acceptable solvates, such as hydrates.
The salts and/or solvates of the compounds of the formula (I) which are not pharmaceutically acceptable may be useful as intermediates in the preparation of pharmaceutically acceptable salts and/or solvates of compounds of formula (I) or the compounds of the formula (I) themselves, and as such form another aspect of the present invention.
A compound of formula (I) may be prepared by amidation of a suitable carboxylic acid with a suitable amine. Accordingly, the present invention also provides a process for the preparation of a compound of formula (I) or a salt thereof or a solvate thereof, which process comprises the amidation of a compound of formula (II) 
wherein;
R1xe2x80x2, R2xe2x80x2, R3xe2x80x2, and R4xe2x80x2 each respectively represent R1, R2, R3, and R4 as defined in relation to formula (I) or a protected form thereof, with a compound of formula (III)
HNRsxe2x80x2Rtxe2x80x2xe2x80x83xe2x80x83(III)
wherein;
Rsxe2x80x2 and Rtxe2x80x2 each represent Rs and Rt as defined in relation to formula (I) or a protected form thereof and thereafter, as necessary, carrying out one or more of the following steps:
(i) converting one compound of formula (I) into another compound of formula (I);
(ii) removing any protecting group;
(iii) preparing a salt or a solvate of the compound so formed.
Suitable amidation methods include treating the compound of formula (II) with a compound of formula (III).
The reaction between the compounds of formula (II) and (III) may be carried out under the appropriate conventional amidation conditions, for example in an aprotic solvent such as dimethylformamide, acetonitrile and tetrahydrofuran, at any temperature providing a suitable rate of formation of the required product, conveniently at ambient temperature; preferably the amidation reaction is carried out in the presence of a peptide coupling reagent such as 1-hydroxybenzotriazole (HOBT), and/or 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (WSC).
A compound of formula (II) may be prepared by cyclising a compound of formula (IV) 
wherein;
R1xe2x80x2, R2xe2x80x2, R3xe2x80x2, and R4xe2x80x2 are as defined in relation to formula (II) and Rp represents a protected carboxyl group or a group convertible into a carboxyl group and thereafter, as required, converting the group Rp into a carboxyl group.
Suitably, the cyclisation reaction is carried out under reductive cyclisation conditions, for example by using powdered iron/acetic acid mixtures or an alkali metal hydrogensulphite, such as sodium hydrogensulphite, in any suitable solvent such as tetrahydrofuran, ethanol, methanol, or water or mixtures thereof, at any temperature providing a suitable rate of formation of the required product, such as an elevated temperature, conveniently at the reflux temperature of the solvent.
When Rp is a protected carboxyl group, suitable groups include lower alkoxy carbonyl groups, for example methoxy or ethoxy carbonyl groups, which may be removed by conventional hydrolysis methods, for example by use of basic hydrolysis using ethanolic potassium hydroxide.
When Rp is a group convertible into a carboxyl group, suitable groups include cyano group. Such groups may be converted into carboxyl groups using conventional methods for example when Rp is a cyano group it may be converted into a carboxyl group by hydrolysis using conventional methods, for example by use of basic hydrolysis using potassium hydroxide solution in ethanol at reflux.
A preferred value of Rp is a cyano group.
A compound of formula (IV) is prepared by reacting a compound of formula (V) 
wherein;
R1xe2x80x2 and R2xe2x80x2 are as defined in relation to formula (II) with a compound of formula (VI) 
wherein;
R3xe2x80x2, R4xe2x80x2, and Rp are as defined in relation to formula (IV) and L1 represents a leaving group, such as a halogen group, for example a chloro group.
The reaction between the compounds of formula (V) and (VI) may be carried out in an inert hydrocarbon solvent, such as cyclohexane, at any temperature providing a suitable rate of formation of the required product, preferably at an elevated temperature, such as the reflux temperature of the solvent and in presence of a base, preferably a tertiary amine such as triethylamine.
The reaction between the compounds of formulae (V) and (VI) proceeds via an intermediate which is not usually isolated and which provides the required compound of formula (IV) on heating in situ. In an alternative aspect, the intermediate is isolated thereby providing an alternative preparation of the compound of formula (IV) wherein the compound of formula (VII) 
wherein;
R1xe2x80x2, R2xe2x80x2, R3xe2x80x2, and R4xe2x80x2 are as defined in relation to formula (II) and Rp is as defined in relation to formula (IV), is heated to provide the compound of formula (IV) as hereinbefore defined.
The conversion of compound (VII) into the compound of formula (IV) is conveniently carried out in a polar solvent mixture, such as dioxane and water, usually at the reflux temperature of the solvent mixture in conditions analogous to those described in J. Het. Chem. 11, 219-221, (1974).
The compounds of formula (V) are known compounds or they are prepared using methods analogous to those used to prepare known compounds, such as those disclosed by Meervein et al Ann. Chem. 641, 1 (1961) and Org. Synth. Collective VII, 34-41.
The compounds of formula (VI) are known, are commercially available, or they are prepared using methods analogous to those used to prepare known compounds, such as those described in J. March, Advanced Organic Chemistry, 3rd Edition (1985), Wiley Interscience.
The compounds of formula (III) are known or they are prepared using methods analogous to those used to prepare known compounds, such as those described in J. March, Advanced Organic Chemistry, 3rd Edition (1985), Wiley Interscience.
Amines of general formula HNRsxe2x80x2Rtxe2x80x2 may be prepared using the methods known in the art for the preparation of amines, for example as taught in Houben-Weil, Methoden der Organischen Chemie, Vol. XI/1 (1957) and Vol. E16d/2 (1992), Georg Thieme Verlag, Stuttgart.
Alternatively a compound of formula (II) may be prepared by cyclising a compound of formula (VIII) 
wherein;
R1xe2x80x2, R2xe2x80x2, R3xe2x80x2, and R4xe2x80x2 are as defined in relation to formula (II) and Rpxe2x80x2 represents a protected carboxyl group or a group convertible into a carboxyl group and thereafter, as required, converting the group Rpxe2x80x2 into a carboxyl group.
Suitably, the cyclisation reaction is carried out using Suzuki reaction conditions, using a palladium catalyst, such as bis(acetonitrile)palladium (II) chloride, in presence of an organic base, such as triethylamine, in any suitable solvent such as tetrahydrofuran thereof at any temperature providing a suitable rate of formation of the required product, preferably at an elevated temperature, such as the reflux temperature of the solvent.
When Rpxe2x80x2 is a protected carboxyl group, suitable protecting groups include alkyoxy carbonyl groups, for example benzyloxy carbonyl, which may be removed by conventional hydrolysis methods, for example by use of basic hydrolysis using ethanolic potassium hydroxide.
A preferred value of Rpxe2x80x2 is a benzyloxycarbonyl group.
A compound of formula (VIII) is prepared by reacting a compound of formula (IX) 
wherein;
R1xe2x80x2 and R2xe2x80x2 are as defined in relation to formula (II) with a compound of formula (X) 
wherein;
R3xe2x80x2, R4xe2x80x2 are as defined in relation to formula (II) and Rpxe2x80x2 is as defined in formula (VIII).
The reaction between the compounds of formula (IX) and (X) may be carried out in an aprotic solvent, such as tetrahydrofuran, at any temperature providing a suitable rate of formation of the required product, preferably from 0-25xc2x0 C., in presence of a palladium catalyst, preferably bis(triphenylphosphine)palladium (II) chloride, and a copper salt, preferably copper (I) iodide.
The compounds of formula (IX) are known compounds or they are prepared using methods analogous to those used to prepare known compounds, such as those disclosed by Yu M. S. et al Tetrahedron Letters, 39, 9347, (1998).
The compounds of formula (X) are prepared by reacting a compound of formula (XI) 
wherein;
R3xe2x80x2, R4xe2x80x2 are as defined in relation to formula (XI) and Rpxe2x80x2 is as defined in formula (VIII) with a compound of formula (XII)
xe2x89xa1xe2x80x94SiMexe2x80x83xe2x80x83(XII)
The reaction between the compounds of formula (XI) and (XII) may be carried out in an aprotic solvent, such as tetrahydrofuran, at any temperature providing a suitable rate of formation of the required product, preferably from 0-25xc2x0 C., in presence of a palladium catalyst, preferably bis(triphenylphosphine)palladium (II) chloride, and a copper salt, preferably copper (I) iodide and in presence of a base, preferably a tertiary amine such as triethylamine.
The reaction between the compounds of formulae (XI) and (XII) proceeds via an intermediate which, if desired, is not isolated, and which provides the required compound of formula (X) by removing the protecting silyl group with n-tetrabutylammonium fluoride. In an alternative aspect, the intermediate is isolated thereby providing an alternative preparation of the compound of formula (X) wherein the compound of formula (XIII) 
wherein;
R3xe2x80x2, and R4xe2x80x2 are as defined in relation to formula (II) and Rpxe2x80x2 is as defined in relation to formula (VIII) is heated to provide the compound of formula (X) as hereinbefore defined.
The compounds of formula (XI) are known compounds or they are prepared using methods analogous to those used to prepare known compounds, such as those disclosed by Buehler, C. A. et al., J. Am. Chem. Soc. 68, 574 (1946).
The compounds of formula (XII) are known, are commercially available, or they are prepared using methods analogous to those used to prepare known compounds, such as those described in J. March, Advanced Organic Chemistry, 3rd Edition (1985), Wiley Interscience.
A compound of formula (I) or a salt thereof or a solvate thereof may be isolated from the above mentioned processes according to standard chemical procedures.
The preparation of salts and/or solvates of the compounds of formula (I) may be performed using the appropriate conventional procedure.
If required mixtures of isomers of the compounds of the invention may be separated into individual stereoisomers by conventional means. For example enantiomers may be resolved by the use of an optically active acid as a resolving agent. Suitable optically active acids which may be used as resolving agents are described in xe2x80x9cTopics in Stereochemistryxe2x80x9d, Vol. 6, Wiley Interscience, 1971, Allinger, N. L. and Eliel, W. L. Eds.
Alternatively, any enantiomer of a compound of the invention may be obtained by stereospecific synthesis using optically pure starting materials of known configuration.
The absolute configuration of compounds may be determined by conventional methods such as X-ray crystallographic techniques.
The protection of any reactive group may be carried out at any appropriate stage in the aforementioned processes. Suitable protecting groups include those used conventionally in the art for the particular group being protected. Protecting groups may be prepared and removed using the appropriate conventional procedure, for example hydroxy groups, including diols, may be protected as the silylated derivatives by treatment with an appropriate silylating agent such as di-tert-butylsilylbis(trifluoromethanesulphonate). The silyl group may then be removed using conventional procedures such as treatment with hydrogen fluoride, preferably in the form of a pyridine complex and optionally in the presence of alumina, or by treatment with acetyl chloride in methanol. Alternatively benzyloxy groups may be used to protect phenolic groups, the benzyloxy group may be removed using catalytic hydrogenolysis using such catalysts as palladium (II) chloride or 10% palladium on carbon.
Amino groups may be protected using any conventional protecting group, for example tert-butyl esters of carbamic acid may be formed by treating the amino group with di-tert-butyldicarbonate, the amino group being regenerated by hydrolysing the ester under acidic conditions, using for example hydrogen chloride in aqueous ethanol or trifluoroacetic acid in methylene dichloride. An amino group may be protected as a benzyl derivative, prepared from the appropriate amine and a benzyl halide under basic conditions, the benzyl group being removed by catalytic hydrogenolysis, using for example a palladium on carbon catalyst.
Indole NH groups and the like may be protected using any conventional group, for example benzenesulphonyl, methylsulphonyl, tosyl, formyl, acetyl (all of which are removable by treatment with alkaline reagents), benzyl (removable either with sodium in liquid ammonia or with AlCl3 in toluene), allyl (removable by treatment with rhodium (III) chloride under acidic conditions), benzyloxycarbonyl (removable either by catalytic hydrogenation or by alkaline treatment), trifluoroacetyl (removable by either alkaline or acidic treatment), t-butyldimethylsilyl (removable by treatment with tetrabutylammonium fluoride), 2-(trimethylsilyl)ethoxymethyl (SEM) (removable by treatment with tetrabutylammonium fluoride in the presence of ethylendiamine), methoxymethyl (MOM) or methoxyethyl (MEM) groups (removed by mild acidic treatment).
Carboxyl groups may be protected as alkyl esters, for example methyl esters, which esters may be prepared and removed using conventional procedures, one convenient method for converting carbomethoxy to carboxyl is to use aqueous lithium hydroxide.
A leaving group is any group that will, under the reaction conditions, cleave from the starting material, thus promoting reaction at a specified site. Suitable examples of such groups unless otherwise specified are halogen groups, mesyloxy, p-nitrobenzensulphonyloxy and tosyloxy groups.
The salts, esters, amides and solvates of the compounds mentioned herein may as required be produced by methods conventional in the art. For example, acid addition salts may be prepared by treating a compound of formula (I) with the appropriate acid.
Esters of carboxylic acids may be prepared by conventional esterification procedures, for example alkyl esters may be prepared by treating the required carboxylic acid with the appropriate alkanol, generally under acidic conditions.
Amides may be prepared using conventional amidation procedures, for example amides of formula CONRsxe2x80x2Rtxe2x80x2 may be prepared by treating the relevant carboxylic acid with an amine of formula HNRsxe2x80x2Rtxe2x80x2 wherein Rsxe2x80x2 and Rtxe2x80x2 are as defined above. Alternatively, a C1-6alkyl ester such as a methyl ester of the acid may be treated with an amine of the above defined formula HNRsxe2x80x2Rtxe2x80x2 to provide the required amide, optionally in presence of trimethylalluminium following the procedure described in Tetrahedron Lett. 48, 4171-4173, (1977).
As mentioned above the compounds of the invention are indicated as having useful therapeutic properties.
Of particular interest is the osteoporosis associated with the peri and post menopausal conditions. Also encompassed are the treatment and prophylaxis of Paget""s disease, hypercalcemia associated with bone neoplasms and all the types of osteoporotic diseases as classified below according to their etiology:
Primary Osteoporosis
Involutional
Type I or postmenopausal
Type II or senile
Juvenile
Idiopathic in young adults
Secondary Osteoporosis
Endocrine abnormality
Hyperthyroidism
Hypogonadism
Ovarian agenesis or Turner""s syndrome
Hyperadrenocorticism or Cushing""s syndrome
Hyperparathyroidism
Bone marrow abnormalities
Multiple myeloma and related disorders
Systemic mastocytosis
Disseminated carcinoma
Gaucher""s disease
Connective tissue abnormalities
Osteogenesis imperfecta
Homocystinuria
Ehlers-Danlos syndrome
Marfan""s syndrome
Menke""s syndrome
Miscellaneous causes
Immobilisation or weightlessness
Sudeck""s atrophy
Chronic obstructive pulmonary disease
Chronic alcoholism
Chronic heparin administration
Chronic ingestion of anticonvulsant drugs
In addition the invention encompasses the treatment of tumours, especially those related to renal cancer, melanoma, colon cancer, lung cancer and leukemia, viral conditions (for example those involving Semliki Forest virus, Vesicular Stonatitis virus, Newcastle Disease virus, Influenza A and B viruses, HIV virus), ulcers (for example chronic gastritis and peptic ulcer induced by Helicobacter pylori), for use as immunosupressant agents in autoimmune diseases and transplantation, antilipidemic agents for the treatment and/or prevention of hypercholesterolemic and atherosclerotic diseases and to be useful for the treatment of AIDS and Alzheimer""s disease. These compounds are also considered useful in treating angiogenic diseases, i.e. those pathological conditions which are dependent on angiogenesis, such as rheumatoid arthitis, diabetic retinopathy, psoriasis and solid tumours.
The present invention therefore provides a method for the treatment and/or prophylaxis of diseases associated with over activity of osteoclasts in mammals which method comprises the administration of an effective non-toxic amount of a compound of formula (I), or a pharmaceutically acceptable salt thereof, or a pharmaceutically acceptable solvate thereof.
In a further aspect, the present invention provides a method for the treatment of osteoporosis and related osteopenic diseases in a human or non-human mammal, which comprises administering an effective, non-toxic, amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof or a pharmaceutically acceptable solvate thereof, to a human or non-human mammal in need thereof.
In a further aspect, the present invention also provides a method for the treatment of tumours, especially those related to renal cancer, melanoma, colon cancer, lung cancer and leukemia, viral conditions (for example those involving Semliki Forest, Vesicular Stomatitis, Newcastle Disease, Influenza A and B, HIV viruses), ulcers (for example chronic gastritis and peptic ulcer induced by Helicobacter pylori), autoimmune diseases and transplantation, for the treatment and/or prevention of hypercholesterolemic and atherosclerotic diseases, AIDS and Alzheimer""s disease, angiogenic diseases, such as rheumatoid arthritis, diabetic retinopathy, psoriasis and solid tumours, in a human or non-human mammal, which comprises administering an effective, non-toxic, amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof or a pharmaceutically acceptable solvate thereof, to a human or non-human mammal in need thereof.
In a still further aspect, the present invention a compound of formula (I) or a pharmaceutically acceptable salt thereof, or a pharmaceutically acceptable solvate thereof, for use as an active therapeutic substance.
In a further aspect, the present invention provides a compound of formula (I) or a pharmaceutically acceptable salt thereof or a pharmaceutically acceptable solvate thereof for use in the treatment or prophylaxis of diseases associated with over activity of osteoclasts in mammals.
In a further aspect, the present invention provides a compound of formula (I) or a pharmaceutically acceptable salt thereof or a pharmaceutically acceptable solvate thereof, for use in the treatment of or prophylaxis of osteoporosis and related osteopenic diseases.
In a further aspect, the present invention provides a compound of formula (I) or a pharmaceutically acceptable salt thereof or a pharmaceutically acceptable solvate thereof for use in the treatment of tumours, especially those related to renal cancer, melanoma, colon cancer, lung cancer and leukemia, viral conditions (for example those involving Semliki Forest, Vesicular Stomatitis, Newcastle Disease, Influenza A and B, HIV viruses), ulcers (for example chronic gastritis and peptic ulcer induced by Helicobacter pylori), autoimmune diseases and transplantation, for the treatment and/or prevention of hypercholesterolemic and atherosclerotic diseases, AIDS and Alzheimer""s disease, angiogenic diseases, such as rheumatoid arthritis, diabetic retinopathy, psoriasis and solid tumours, in a human or non-human mammal.
A compound of formula (I), or a pharmaceutically acceptable salt thereof or a pharmaceutically acceptable solvate thereof, may be administered per se or, preferably, as a pharmaceutical composition also comprising a pharmaceutically acceptable carrier.
Accordingly, the present invention also provides a pharmaceutical composition comprising a compound of formula (I) or a pharmaceutically acceptable salt thereof or a pharmaceutically acceptable solvate thereof and a pharmaceutically acceptable carrier therefor.
Active compounds or a pharmaceutically acceptable salt thereof or a pharmaceutically acceptable solvate thereof are normally administered in unit dosage form.
An amount effective to treat the disorders hereinbefore described depends upon such factors as the efficacy of the active compounds, the particular nature of the pharmaceutically acceptable salt or pharmaceutically acceptable solvate chosen, the nature and severity of the disorders being treated and the weight of the mammal. However, a unit dose will normally contain 0.01 to 50 mg, for example 1 to 25 mg, of the compound of the invention. Unit doses will normally be administered once or more than once a day, for example 1, 2, 3, 4, 5 or 6 times a day, more usually 1 to 3 or 2 to 4 times a day such that the total daily dose is normally in the range, for a 70 kg adult of 0.01 to 250 mg, more usually 1 to 100 mg, for example 5 to 70 mg, that is in the range of approximately 0.0001 to 3.5 mg/kg/day, more usually 0.01 to 1.5 mg/kg/day, for example 0.05 to 0.7 mg/kg/day.
In such treatments the active compound may be administered by any suitable route, e.g. by the oral, parenteral or topical routes. For such use, the compound will normally be employed in the form of a pharmaceutical composition in association with a human or veterinary pharmaceutical carrier, diluent and/or excipient, although the exact form of the composition will naturally depend on the mode of administration.
Compositions are prepared by admixture and are suitably adapted for oral, parenteral or topical administration, and as such may be in the form of tablets, capsules, oral liquid preparations, powders, granules, lozenges, pastilles, reconstitutable powders, injectable and infusable solutions or suspensions, suppositories and transdermal devices. Orally administrable compositions are preferred, in particular shaped oral compositions, since they are more convenient for general use.
Tablets and capsules for oral administration are usually presented in a unit dose, and contain conventional excipients such as binding agents, fillers, diluents, tabletting agents, lubricants, disintegrants, colourants, flavourings, and wetting agents. The tablets may be coated according to well known methods in the art.
Suitable fillers for use include cellulose, mannitol, lactose and other similar agents.
Suitable disintegrants include starch, polyvinylpyrrolidone and starch derivatives such as sodium starch glycollate. Suitable lubricants include, for example, magnesium stearate. Suitable pharmaceutically acceptable wetting agents include sodium lauryl sulphate.
These solid oral compositions may be prepared by conventional methods of blending, filling, tabletting or the like. Repeated blending operations may be used to distribute the active agent throughout those compositions employing large quantities of fillers. Such operations are, of course, conventional in the art.
Oral liquid preparations may be in the form of, for example, aqueous or oily suspensions, solutions, emulsions, syrups, or elixirs, or may be presented as a dry product for reconstitution with water or other suitable vehicle before use. Such liquid preparations may contain conventional additives such as suspending agents, for example sorbitol, syrup, methyl cellulose, gelatin, hydroxyethylcellulose, carboxymethyl cellulose, aluminium stearate gel or hydrogenated edible fats, emulsifying agents, for example lecithin, sorbitan monooleate, or acacia; non-aqueous vehicles (which may include edible oils), for example, almond oil, fractionated coconut oil, oily esters such as esters of glycerine, propylene glycol, or ethyl alcohol; preservatives, for example methyl or propyl p-hydroxybenzoate or sorbic acid, and if desired conventional flavouring or colouring agents.
For parenteral administration, fluid unit dose forms are prepared containing a compound of the present invention and a sterile vehicle. The compound, depending on the vehicle and the concentration, can be either suspended or dissolved. Parenteral solutions are normally prepared by dissolving the compound in a vehicle and filter sterilising before filling into a suitable vial or ampoule and sealing. Advantageously, adjuvants such as a local anaesthetic, preservatives and buffering agents are also dissolved in the vehicle. To enhance the stability, the composition can be frozen after filling into the vial and the water removed under vacuum.
Parenteral suspensions are prepared in substantially the same manner except that the compound is suspended in the vehicle instead of being dissolved and sterilised by exposure to ethylene oxide before suspending in the sterile vehicle. Advantageously, a surfactant or wetting agent is included in the composition to facilitate uniform distribution of the active compound.
For topical administration, the composition may be in the form of a transdermal ointment or patch for systemic delivery of the active compound and may be prepared in a conventional manner, for example, as described in the standard textbooks such as xe2x80x98Dermatological Formulationsxe2x80x99xe2x80x94B. W. Barry (Drugs and the Pharmaceutical Sciencesxe2x80x94Dekker) or Harrys Cosmeticology (Leonard Hill Books).
Accordingly, the present invention provides the use of a compound of formula (I), or a pharmaceutically acceptable salt thereof, or a pharmaceutically acceptable solvate thereof, for the manufacture of a medicament for the treatment and/or prophylaxis of diseases associated with over activity of osteoclasts in mammals.
In a further aspect, the present invention provides the use of a compound of formula (I), or a pharmaceutically acceptable salt thereof, or a pharmaceutically acceptable solvate thereof, for the manufacture of a medicament for the treatment and/or prophylaxis of osteoporosis and related osteopenic diseases.
In a still further aspect, the present invention provides the use of a compound of formula (I), or a pharmaceutically acceptable salt thereof, or a pharmaceutically acceptable solvate thereof, for the manufacture of a medicament for the treatment of tumours, especially those related to renal cancer, melanoma, colon cancer, lung cancer and leukemia, viral conditions (for example those involving Semliki Forest, Vesicular Stomatitis, Newcastle Disease, Influenza A and B, HIV viruses), ulcers (for example chronic gastritis and peptic ulcer induced by Helicobacter pylori), autoimmune diseases and transplantation, for the treatment and/or prevention of hypercholesterolemic and atherosclerotic diseases, AIDS and Alzheimer""s disease, angiogenic diseases, such as rheumatoid arthritis, diabetic retinopathy, psoriasis and solid tumours.
No unacceptable toxicological effects are expected with compounds of the invention when administered in accordance with the invention. As is common practice, the compositions will usually be accompanied by written or printed directions for use in the medical treatment concerned.
The following, descriptions, examples and pharmacological methods illustrate the invention but do not limit it in any way.